Combined contractile spring and retarding device



E. S. COFFMAN.

COMBINED CDNTRACIILE SPRING AND IIETAIIDING DEVICE.

APPLICATION FILED APR 4. 1917. RENEWED FEB. 8| 1919.

Patented Mar. 16, 1920.

N INI I@ m ww R. DN. w Y \m..\m y `N QN. m IE ,UF mw H F L L .lr L P I .N1 m1 1 HIIM MIU NN N sTArEs PATENT onnrcn S. COFFMAN,

OF CLIFTON FORGE, VIRGINIA, ASSIGNOR TO FRANK E. STEBBINS, OF'WASHINGTON, DISTRICT OF COLUMBIA.

COMBRTED CONA'TRACTILE SPRING- RETARDING DEVICE.

-- Application led Apri1 4, 1917, Serial No. 159,829.

To all 'whom t may concern:

Be it known that. I, EDWARD S. 'C0FFMAN,

c a citizen of the United States, residing at) Clifton Forge, in the county of-Alleghany and State of Virginia, have invented a certain new and useful Combined Contractile Spring and Retarding Device; and I do hereby declare the following to be a full,

clear, and exact description of the invention,

such as will enable others skilled in the art to which it appertains to make and use the same.

The present application is in part a continuation of my applications iiled respectively on November 6, 1909, Serial No. 526,602, and February l2, 1913, Serial No, 7 47 ,933; said latter application being in part a continuation of my application filed December-30, 1909, Serial No. 535,672,

The main object or purpose in mind in making the invention was the provision of Aa combined contractile helical spring and Y of effective operation, and very unsatisfac- Y tory for other reasons when the attempt was made to remedy their defects.

,Cnsequently, and after extended experiments, I devised a novel combined contractile helical spring and regulative retarding device, eifectively attaining the ends above recited, .by combining with suitable telescopic body members provided 'with a substantially closed variable air chamber and l having an adjustable valve for controlling the quantity of air in the chamber whenthe I members telescope together, a compact helical spring concealed within the members and having its opposite ends positively secured to the opposite members, so that when contracted or slightlyunder tension the spring Specification of Letters Patent.

Renewed February 8, 1919. Serial No. 275,850.

would hold the members together, and also that when expanded with the outward telescopic movement of one member relative to the other the contractile energy of the spring would automatically return the extended member to its seat, a simultaneous checking and retardlng .effect upon the spring and ymember 1n thelr movements being secured corresponding to the variation of the quantity of air in the chamber controlled and regulated by the adjustable valve.d

Accordingly my invention consists in a combined contractile spring and positive retarding device having novelties of construction and combined parts substantially as herein set forth and claimed.

The accompanying drawing illustrates two examples of the embodiment of the invention, slightly different in details, constructed and the parts combined according to the best modes of procedure I have so far 'devised for the purpose, also one example of the use ofithe device; it being understood that the same 1s designed for actuating various movablethings or parts, hinged or'` othervwise, t'or in. connection with .machines or structures, with whichthe device may be operatively combined' or associated, for ex; ample, to return a valve to its seat, or return a reciprocating carrier.

Patented Mar. 16,1920.'

Figure l is a longitudinal sectional view in elevation of the combined device, except a small portion shown in full exterior ele vation. 1

Fig. 2 is a similar view:of another example, the contractile spring and its attachments being shown in elevation and other parts in longitudinal section.

Fig. 3 is a cross section of Fig. 4 shows in yelevation view atype of v the device applied for use in connection with a vehicle frame and a semi-elliptic spring. hThe synthetic combination, shown by cachot1 the examples, may be analyzed into abstract parts and identified as follows:

In the example lshown by Fig/il the letter lA designates an exterior hollow body member, in this instance a metallic `tube,'pro

vided withy exterior threads 1' and 2 at opposite ends; B, a substantially closed head at one end having threads' 3l matching th threads 1 and C a head at the opposite end with threads 4 matching the threads 2 of the tube, and provided with a central opening 5 constituting a bearing. The head B has an eye D brazed to the head.

E designates an interior hollow body member, in this instance a metallic tube, provided with exterior threads 9 and slots 10 at the left hand end and with threads 11 at the other end on the exterior surface, said tube being located and movable within the opening '5 in head C and projecting beyond the said head so it can be attached.

F designates a threaded closure for the projecting end of tube E. VIn the form of a cap it screws on the threads 11.

On the inclosedl threaded end of member E is a hollow piston or plunger comprised of a hollow threaded ring or washer 13, a cup-shaped flexible -packing 141 of leather or other suitable material, and a Y threaded follower or clamping ring 15, the

cup packing facing the head B and adapted frictionally to `engage the interior surface of member A and form a tight joint when subjected to greater than atmospheric pressure, but which packing can yield and allow air to pass from the space back of it to the space in front of it. The ring 13 is of slightly less diameter than the tube A so as to provide a small open space 16 for the passage of air or fluid downwardly and between the packing and inner surface of the exterior member.

S is a contractile helical spring located mainly within the interior tubular member when seated, the spring normally being Slightly under tension, as shown, andssecured at one end to the eye D on the head B and the other end secured to the said interior tube direct-lv bv a bar 17, as shown.

.The device may be attached in operative position by screws in holes 2O through the head B, and a slide 21, adjustable by setscrew 22, on the inner -bodv member.

By the construftions and combinations of; parts two substantially closed air or iuid chambers are formed-a principal or main chamber H including the space inside the two tubes or members bounded by the headd` B, the closure F and the packing, and a second chamber I including the space above the packing and below the head C and between the exterior andv interior memberseach of said chambers being of -variable capacity as the interior tube is reciprocated relative to the exterior member.

. To control the flow of air into andout of these chambers, in addition to the small openv space 16 before mentioned, adjustable `valves may be provided, valve K located 'f'ywithin an opening in the cap F, and valve L located within an opening former being the main valve.

^ Obviously, when the inner telescopic memin head C, the

ber is drawn out and the spring is expanded the control of the discharge of air from the chamber H will determine the degree of the checking or retarding eect upon the contracting spring and inwardly moving telescopic memben Under like conditions the control of air entering the chamber I by valve L will determine the checking or retarding eect in a similar way. When the inner telescopic member is drawn out and the spring yexpanded simultaneously air quite freely passes to chamber H from chamber I back of the piston and packing by way of the small. opening 16, and also by way of the valve K. At the same time air in chamber I can pass out through valve L. However, chamber I may be ignored when there is a very large opening or space for the passage of air to and from the same; and also'when the inner body member is of slightly less diameter than the outer body member, one air chamber only-chamber H then being formed, as the control of the discharge of airlfrom-this chamber H is suiicient to secure the desired checking or retarding effect. In briefer statement air enters chamber H quite freely while the insmall area secures the desired retardation when the work to be done is constant, but

lwhen the period/of time in which the work to be done varies or the device is to be ap*- plied to do different amounts of work the adjustable valve works well and is preferably employed. Obviously, the adjustable valve K'allows the degree of retardation to be controlled and the contractile energy of the sprin to be utilized through different periods o time.

In the example shown by Figs. 2 and 3 the letter A designates an exterior hollow body member, in this instance a metallic tube of suitable length and diameter, provided with interior threads 1 and 2" at opposite ends; B', a substantially closing head atone end having exterior threads 3 matching the threads 1'; and C a head at the opposite end with exterior threads L1"matching the interior threads 2 of the tube, and provided with a central opening 5 constituting a bearing.

The head B has an eye D which is part of the plug 6 having a hole 7 at one end for attachment and threaded at the other end to engage the threads defining the opening 8 in the head. J

E designates anA interior hollow body member, in this instance a metallic tube, provided with exterior threads 9 and slots 10 at the left hand end and with interior threads 11 at the other end, said tube being located and movable within the opening 5 in head C and projecting beyond the said head so it can be attached.

FNdesignates a threaded closure for the projecting end oftube E', in the lform of a plug, and it engages the threads 11, the plug having a hole 12 for attachment.-

On the inclosed threaded end of the member E isa hollow piston or plunger comprised of a hollow threaded ring or washer 13, a cup-shaped flexible packing 14; of

leather or other suitable material, and a.

threaded follower or clamping ring 15', the cup packing facing the head B and adapted f frictionally to engage the interior surface of member A and form a tight joint when subjected to greater than atmospheric air pressure, but which packing can yield and allow air to pass from the space back of it to the space in front of it. The 4ring 13 is of slightly less diameter than the tube A so as to provide a small open space 16 for the passage of air downwardly and between the packingv and inner surface of the exterior member.`

S is a 'contractile helical spring located mainly within the interior tubular member when seated, the spring normally being slightlyv under tension, as shown, and secured at one end to the eye D on the head B and the other end secured to the said inf terior tube mediately through a threaded rod 18 and threaded washer 19 thereon car- Y ried by the plug which closes the end of the tube. When unscrewedfrom the tube, the plug and rodl may be screwed into the washer and the spring expanded to increase its tension or to take up possible slack due to permanent set.

It will be clear from the constructions and combinations of parts two substantially closed air chambers are formed--a principal or main chamber H including the space inside the two tubes or members bounded by the head B, the closure F and-the`packing, and a second chamber I including the space above the packing andv below the head C and between the exterior and interior memberseach of said chambers bein of variable capacity as the interior tu e is reciprocated relative to the exterior member.

To-control the flow of air into and out. of these chambers, in addition to the small open space 16 before mentioned, a small open space 23 may be provided between the head C and the interior tube, and also an adjustable valve M located within the head B', as shown, the same consisting of a threadedsrew ith .part bf the metal removed and adj ustlably seated within the hole in the head whereby the area ofthe air passage can be varied. l

Obviously, when the inner telescopic member is drawn out and the spring is eX- panded the control of the discharge of air from chamber H will determine the degree of the checking or retardin efect upon the contracting spring S an the .inwardly moving telescopic member E. The size of the opening 23 by ywhich air can pass to chamber I will also determine in a degree the checking or'retarding eEect. When the inner telescopic member is drawn out and the spring expanded simultaneously air uite freely passes to chamber H from c amber I back of the piston and packing by way of the small opening 16', and also by way of the valve M. At the same time alr in chamber I can pass out through the small open space 23.

However, chamber I may be ignored' when there is a very large opening or space for the passage of air to and'from the same; and also when the inner body member is of 'slightly less diameter than the outer body member, one air chamber only-chamber H"-then being formed, as the control of the discharge of air from this chamber H is suiicient to secure the desired checking or retarding elfect.

In briefer statement, 'air enters chamber H quite freely while the inner member E is being drawn out and the spring S expanded, so there is no substantial retardation of movement other than overcoming the energy of the spring, butwhen the spring is automatically contracting and drawing the member inwardly the passlng of the air out of chamber H is restricted according to the area of the small discharge opening and there is a checking or retarding of the movement. The inner member can thus be drawn with retardation.

I have found that a permanent opening of small area from chamber H secures the desired retardation when the work to be done is constant, but when the period of A time in which the work to be done -varies or thedevice is to be applied to do dilferent amounts of work an adjustable valve, like M or otherwise, is preferably employed.

y The adjustable valve Aallows the degree of retardation to be controlled and the contractile ener of the spring to be utilized through different periods of time.

To provide for an unretarded movement of the inner member and free contraction of the spring near the, end of the inward travel the by-pass passage X may be formed in the outer member to allow air to pass frm V cylinder, the spring in such devices being` short distance or a few inches.

35, a lever device pivoted to a bracket 36 f with one arm in pivotal connection with said telescopic interior member and the -y other arm pivoted to one end of the spring.

The rocking of the lever reciprocates the interior member which is retarded in its inward movement and acts as a shock absorber.

I am aware that devices have been designedrcomprising a piston, piston rod and helical spring inclosed within a cylinder, the spring surrounding the piston rod back of the piston and with its ends loosely bearingv against the piston4 and closed end of the designed to dothe work by expansive or recoil lenergy after being compressed. Such devices are practical generally only when the elongation of the spring upon recoilA after compression is limited to a relatively Where the travel of the parts to be actuated by the spring is much greater, such devices are impracticable, and' attempts to remedy their defects by increasing the number of coils or the pitch of the coils or changing the elas-v ticity of the wire constituting the coils, have been found ineffectual and unsatisfactory for many reasons.y

In distinction therefrom and as the result of extended experiments I emplo the contractile energy of an expanded helical spring of relatively light weight and small dimen.

sions to do the required automatic work, which spring admits of expansion and contraction through a relatively great distance and which can be`inclosed within a small space out of sight and protected from rust and injury, the ends of the helical spring being attached to the parts which are to be actuated or movedy one relative to the other.

. In my application for Letters Patent filed February 12, 1913, Serial No. 747,933, I have shown and described a combination of elements comprising a door, a -door casing, a contractile spring and retarding device, and attachments, all designedly coperating and functioning to close and control the closing movement of the door. In the present application a part of the whole combination therein disclosed-the f contractile spring and retarding device only--is abstracted therefrom and separately claimed.

What I claim is:

1. The combination of two hollow telescopic body members the outer one substantially'closed at both ends and one of said ends having a bearing for the inner member which latter is located and movable within the bearing, the outer end of the inner member being closed and the opposite end open, a contractile helical spring within and connected to both members and normally holding them together, and means between the inner member and the inner surface of the outer member forming a substantially tight joint, whereby two substantially closed fluid chambers are formed between the members.

2. The combination of a hollow outer body member and a hollow piston rod telescopically mounted within a bearing supported by the outer member, said outer member and hollow piston rod being closed at their extreme outer ends, a contractile heli.- cal spring within the hollow piston rod and outer member and connected at one endto said rod and at the other end to the outer member, and 0a hollow piston or plunger carried by the rod forming a substantially closed chamber of variable capacity.

3. The combination of telescoping inner and outer hollow body members, means for substantially closing theend of the outer member, a bearing for the inner member said inner member having an extension outside and being movable within said, bearing, means for forming a substantiallytight joint between the members and with the outer member forming a substantially closed chamber of variable capacity, and a contractile coiled spring under tension within and positively connecting and normally holding together the two members; means being provided for the admission of fluid to and its discharge from said chamber.

4. The combination of outer and inner telescopic hollow body members the inner one having an extension outside the other both substantially closed at their extreme outer ends the inner member having an open end and both together forming a substantially closed variable u'idvchamber, a concealed contractile helical spring within and positively connecting the members said spring when contracted holding the -members together, and means adapted for attaching the members in operative position.

5. The combination of outer and inner telescopic hollow body members'both substantially closed at their extreme outer ends the inner one having an open end and also having an extension beyond the other, means for forming L joint between the telescoping members and providing a substantially closed variable Huid chamber, a concealed for attachment, a contractile helical spring p within the tubes having its opposite ends connected to the opposite tubes and when Slightly, under tension holding them together," and means for securing a gradual checking or retarding effect on the relative movement of thev tubes when the tubes, relatively moved apart and the spring expanded,

fare forced together bythe contractile energy of the spring.

7. The combination of two telescopic tubes one extended beyond the other and adapted for attachment, a contractile helical spring within the tubes having its opposite ends connected to the opposite tubes and when slightly under tension holding them together, and means for securing different retarding effects or speeds when the tubes, relatively moved apart and the spring expanded, are forced together by the contractile energy of the spring. x

8. The combination of telescopic hollow body members the end of one being extended beyond the other for attachment, a contractile helical spring under tension within and its opposite ends connected respectively to the opposite members and normally holding them together, andl means, when the vmembers are moved apart and the spring expanded, actingy in opposition to the spring and retarding the contractile energy of the same.

9. The combination of inner and outer telescopic hollow body members, the inner one extended outside the other and both substantially closed to form a variable iuid chamberLa contractile helical spring within and positively connecting the two members, and means for permittin the 'passage of fluid into and its gradua passage out of said chamber to obtain aretarding effect.

10. The combination of telescopmg inner and outer hollow` body members the inner one extending be ond the other'for attachment, a packing fyorming with said members a substantially closed variable fluid chamber, a spring within positively connecting the two mem ers and normally holding them together, means for allowing iuid quite freely to pass out of said chamber when the members are moved apart and the spring expanded, and means for checking the contractile energy of the spring and retarding the inward movement of one'member relative to the other.

11. A combined contractile spring, and retarding device, including telescopic body members one of them tubular and having an extension beyond the other, a suptelescope together under the contractile en-l ergy of the spring.

12. A combined contractile spring and retarding device, including tubular body members telescopically mounted one within the other the outer ends being substantially closed, a contractile helical spring within and positively connecting said opposite members, a packing secured upon the inner body member, a valve in connection with one of the members, and means adapting the device for attachment. V

13. A combined contractile spring and retarding device, including two telescopic tubular body members, one having an extension beyond the other, closed to provide a variable air cham'ber, means for admitting air to the cliamber, means for restricting the passage of air out of said chamber for the purpose set forth, and a contractile helical spring within and connecting the inner and outer members.

14. The combination of telescopic outer 'and inner members, the interior member ends connected to the opposite members and when contracted holding them together; a fluid chamber of variable capacity in operative connection with the members; and means for allowing the gradual variation of the quantity of liuld in the said chamber to secure a retarding effect when the members, relatively moved apart and the spring expanded, are relatively forced together by the contractile ener of the spring.

15. The comblnation of telesopic outer and inner members, the interior member having an extension beyond the vend of the other for attachment; an inside concealed contractile helical spring with its opposite ends connected to theopposite members and when contracted holding them together; a fluid chamber of variable capacity in operative conhecti'on with the members; and adjustable means for allowing different gradnection therewith a substantially closed fluid chamber of variable capacity, the interior member having an extension beyond the outer for attachment and carrying a v piston or(plunger located and movable within the sai chamber; and an inside concealed contractile helical spring positively attached to opposite members and when contracted holding them together; and said pisl 10 ton or plunger gradually varying the quantity of fluid in the chamber to secure a retarding effect when the members, relatively moved apart and the spring expanded, are relatively forced together by the contractile energy of the spring.

17. The combination of outer and inner telescopic members, the inner member having an extension beyondI the other adapting it for exterior attachment; means for forming a substantially closed variable Huid chamber in operative connection with the members; a concealed contractile helical spring within and connecting the members and normally holding them together; means for gradually varying the quantity of fluid in the chamber and allowing its free passage in one direction but retarding its flow in the other direction, whereby the relative outward movement of the inner member is free and its reverse movement retarded.

18. The combination of outer and inner telescopic body members one member being tubular and having an extension beyond the other for attachment; a contractile helical spring inside the tubular member with one end secured thereto and the other end extended and secured to the other member and normally holding said members together; and a uid chamber of varying capacity in operative connection with .said members;

said exterior member; a contractile vhelical spring also inside and having its opposite ends connected respectively to the opposite members; and a piston or plunger carried by the interior member and located and mov- '55 able within the said chamber; all for the purpose set forth.

20. The combination of two telescopic bodyymembers, the interior one being hollow to receive a spring and extended beyond )the other for attachment, substantially closed to form an air chamber of variable capacity; a contractile helical spring within and connected to the opposite members and when contracted holding them together; and

means for gradually varying the quantity of air within the\`chamber to secure a checking or retarding effect when the members,

relatively moved apart and the spring expanded, .are forced together by the contractile energy of the spring.

21. The subject-matter of claim 20 when the means bounding the air chamber has a relatively Small opening restricting the passage of the air suiciently to secure the desired retardin effect.

22. The subject-matter of claim 20 when the means for varying the quantity of air in the chamber consists of an adjustable valve device to secure different retarding effects.

23. The subject-matter of claim v20 with the addition of means between the body members to form a suiiciently tight joint to retain air in the chamber.

24. The subject-matter of claim 20 with the addition of a packing and a ring engaging the packing and interior member and constituting a hollow piston or plunger for the passage of the spring.

25.l The subject-matter of claim 2O with the addition of means for allowingl air to quite freely pass to the air chamber when its capacity increases.

26. The subject-matter of claim 20 `with the addition of a packing which allows air to pass from the space above the packing and into the space below the packing when the members telescope apart and vice versa when the members telescope reversely.

27. The subject-matter of claim 20 with the addition of means for taking up slack or varying the tension of the spring.

28. The subject-matter of claim 20 with the addition of means for suddenly reducing the air pressure in chamber H and unchecking the spring to increase the momentum of the interior member as' it approaches its seat.

29. The subject-matter of claim 20 with the addition of a detachable'head at\the outer end of one of the members to allow the attachment of one end of the inserted spring.

30. The combination of two telescopic body members one of them hollow to receive a spring and to form a substantially closed variable airv chamber between .the members in all their relative positions each of said members being provided with means adapting it for separate pivotal attachment, and a contractile helical spring within the hollow member and connected with each of said members; there beingA provided in connection with said members an opening of relatively small sectional 4area for the gradual passage of air to secure. a retarding or cushloning effect when the members moved apart and the spring expanded are telescoped together by the contractile energy of the spring.

31. The combination of telescopic outer and inner members, the outer member being hollow closed at one end and having an opening at the other to receive the inner member which constitutes a reciprocating plunger, said members forming a substantially closed fluid chamber of variable capacity but having in connection therewith means for allowing the passage of fluid to and its passage from said chamber, an inside concealed contractile helical springone l end positively attached to the outer member and the other end positively connected with the inner member and when contracted holding the members together; and said inner member acting as a plunger gradually varying the quantity of fluid in theJ chamber to secure a retarding'effect when the members relatively moved apart and the spring 'expanded are relatively forced together by the contractile energy of the spring.

32. The combination in a retarding desubstantially closed at the other end, said inner member carrying a yieldable packing -forming with the outer member an air chamber of variable capacity and said packing when subjected to pressure greater than atmospheric pressure making a substantially .tight frictional joint between the members, and a contractile helical spring with its axis inline with the axes of the said members and itsr opposite ends secured to the opposite members and holding the members together; the means forming the air chamber being so designed and constructed that when the members are moved apart and the spring expanded the flow of air from the chamber will be restricted and retarded to retard the inwardly telescopic movement. f

EDWARD COFFMAN. 

